Photo Backup software : Photo Backup 2.6.0 does ‘backup by contents’, making archives completely independent of photo cataloging, organizing and editing. Unlike simple photo backup applications, Photo Backup calculates a unique signature for each photo based on its contents. This signature is saved and later used to compare photos. It guarantees that whenever a photo is edited, it will be archived again. You’ll have access to all photo revisions and be able to see their different thumbnails. By keeping archive history according to file contents, archives are now independent of photo names, locations, and dates. Because Photo Backup tracks photos by their contents, the backup information is never lost. It’s maintained for all photos.